Rubber-sheeting mill



(No Model.)

N. C. MITCHELL. RUBBER SHEETING MILL.

No. 418,645. Patented 1390.24, 1&889.

N. Pinks.. Pwnnnugmnner. washing n c.

the rubber from overheating.

i' UNITED STATES APATENT OFFICE.

NATHANIEL C. MITCHELL, OF PHILADELPHIA, PENNSYLVANIA.

RUBBER-SHEETING MILL.

SPECIFICATION forming part of Letters Patent No; 418,045, dated December 24, 1889.

Application tiled October 3,

To all whom it may concern.-

Be it known thatI, NATHANIEL C. MITCHELL, of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a new and useful Improvement in Rubber- Sheeting Mills, which improvement is fully set forth in the following speciiicatiou.

This invention has reference to the construction of mills for rolling and sheeting rubber.

The ordinary sheeting-mill consists, simply, of a pair. of smooth-faced rolls supported in bearings in a strong fraine,between which rolls the rubber is carried until it is formed into a sheet, which adheres tenaciously to one of the rolls and has eventually to be severed by a knife and pulled oit. The adherence of the sheet to the roll keeps the heat in the latter, rendering it necessary to drive the rolls at a very low speed to prevent injury to Moreover, the operation of detaching the sheet, besides being difficult and awkward, is extremely dangerous, requiring great care on the part of the workmen to avoid accident. i

According to the present invention the mill comprises a series of, say, tive rolls ,supported in the same framein such manner that the rubber passes between the first and second rolls, then between the second and third, and so on, receiving in its course through the mill as many nips as there are rolls, less one. The sheet does not adhere to one of the rolls, so that the use of a knife for detachment is avoided, and, furthermore, theliability to injury of the rubber by overheating is lessened, making it possible to drive the rolls at a comparatively high rate of speed.

In a concurrent application filed September 26, 1889, Serial No. 325,193, I have described an improvement in the art of restoring rubber, which improvement consists, essentially, in

rolling the rubber stock while in a moist condition, and the mill described herein is designed specially for carrying out such process, though obviously its use is not confined thereto.

' The accompanying drawings, which form part of this specification, illustrate a mill constructed in accordance wit-h the invention, Figure I being a vertical section, and Fig. II an elevation.

889- Seral No. 325,898. (No model.)

The frame consists of several castings rmly but detachably fastened together. At each end of the mill there is a front upright casting A and a rear casting B, which are substantially alike, except that the upright B is somewhat taller than A. These uprights have longitudinal strengthening-ribs a b. Between the uprights A B is the intermediate casting C, (one at each end.) The shape of casting C is shown in Fig. I. It is provided on each side with a series of horizontal arms c, forming between them recesses for the reception and support of the journalboxes I) (dot-ted lines, Fig. I) of the several rolls, which it in said recesses. As shown, there are three of these recesses on the rear side of the mill and two on the front side, making supports for five rolls; but the construction of the frame-work could readily be modified to support a greater or less number, if desired. Casting C iits snugly between the uprights A B, to which it is firmly secured by bolts d.

At the top of each side frame is a cap-piece E, provided at each end with a downwardlyprojecting shoulder e. These shoulders it over the upper ends of uprights A B and prevent them from spreading. The cap-pieces E are fastened to casting C by bolts f, and the two cap-pieces are connected and braced by the rods F. Other tie-rods G connect the uprights A A and B B. The rolls 1 2 3 4 5 are supported in their respective journal-boxes D, which are slipped into the recesses in casting C, as already described. Roll 3 is of larger diameter than the others, and from it the other rolls are driven. Roll 3 may be about eighteen inches in diameter and the other Vrolls sixteen inches; but these dimensions are variable. The driving-shaft I-I has a pinion h, which engages a large spur-gear I. on the shaft of roll 3. At the other end of the mill is a train of gears 6 7 8 9 on the shafts of rolls 1, 2, 4, and 5, respectively, and driven from a gear-wheel on the shaft of roll 3. The direction of rotation of all the rolls is indicated by the arrows in Fig. I. Each roll rotates in the opposite direction to the one adjacent to it. The gearing should preferably be such that the large roll 3 makes, say, twenty-tive revolutions per minute, while the smaller ones make thirty. This would give to all the rolls IOC these jack-bolts the position of each rollcan be adjusted independently of al1 the others. Should it be necessary to remove any one of the rolls, this can be effected without disturbing any of the others by first taking olf the top pieces or caps E'and then unbolting and tionand the manner in which the same is or Vmay be carried into effect, what I claim as removing the uprights A or B, as may berequired to give access to the desired roll, which leaves the journal-boxes of the roll'free to be withdrawn horizontally from the recesses in the supporting-castings C.

By the arrangement of the rolls, as shown, one below the other, andY with their axes alternately" to the right and leftofa vertical plane, several important advantages' are secured. It enables four'p'inchesornips to be given tothe rubber with five rolls, or, in other words, enables five rolls to do the work which heretofore required four pairs' of rolls. It

makes a very compact machine', occupying i ;bination,vwith a series of rolls, of a frame butlittle, if any, morev floor-space in thefac tory than a single mill now takes up; Aand it permitsthe adjustment of eachl roll independently of the others, so that the space betweenl eaclr roll and the oneA adjacent toit (either above or'below) can be regulated toa nicety Furthermore, the described arrangementeffects the feed or passage ofthe rubber through the machine Without speciall devices for this specification in the presence of two subscrib- 1 purpose or manual interference;

As shown in Fig. l, the rubber after passing the space between 2 and 3. After passing again passed through the mill, if desired.

Guide-blocks lm, are arranged Yat the ends of st-ruction and arrangements of parts could be `modified without departing from the spirit of the invention.

Having now fully described my said invenneW, and desire to secure by Letters Patent,

l. In a mill for grindingor sheeting rubber,

l-.the combination, with'aseries ofrolls, of supporting-castingshaving on eachside recesses ..forth'e journal-boxes of said'rolls of sufficient insize to permit horizontal adjustment of said journal-boxes, upright castings, one on each .side of the su ppo'rting-castin gs, and yadj ustingy bolts carried by said uprights, substantially as described.

2. In a grinding or sheeting mill, thecoml comprising castings having on each side horizontal arms forming recesses for the journal- .boXes of said-rolls, upright castings confining ithe journal-'boxes in said recesses, and capi pieces connecting the front and rear uprights, the parts being all firmly bolted together, subastantia'lly as described.

In testimony whereof I have signed 'i this ing witnesses. between rolls 1 and 2 falls upon roll 3, the direction of whose rotation carries it through l 1v NATHANIEL C. MITCHELL.'

Witnesses:

J oEL H. LEEDS, E. M. MUNDY. 

